This invention relates to a multiphase (i.e., moisturizing characteristics. The multiphase emulsion composition is in the form of an oil phase/water phase/silicone fluid phase ("o/w/s multiple emulsion"). In addition to its skin moisturizing activity, the subject o/w/s multiple emulsion may be used as a base form for various products requiring an emulsified dispersion system such as cosmetic and topical drug formulations.
Single emulsion skin care preparations, such as lotions and creams, of the oil-in-water (o/w) type and water-in-oil (w/o) type are well known in the cosmetic art and are in daily use by consumers, the o/w type being more commonly utilized. Multiphase (i.e., double) emulsion compositions, such as the water-in-oil-in-water (w/o/w) type, for example see U.S. Pat. No. 4,254,105, and the oil-in-water-in oil (o/w/o) type, are of lesser commercial significance to date in the cosmetic field. In general, such single or multiphase emulsions contain water, emollients and emulsifiers as essential ingredients and cosmetically acceptable optional additives such as preservatives, antioxidants, skin conditioners, humectants, thickeners, cleansers, colorants, odorants and other components generally utilized in the cosmetic art.
To date, applicants are unaware of a skin moisturizing multiphase emulsion composition of the o/w/s type wherein "s" consists essentially of a silicone fluid. In U.S. Pat. No. 4,013,475, which represents the closest prior art known to applicants, although in an unrelated field, there is described a double emulsion wax polish for treating hard surfaces such as wood or metal. This double emulsion composition is a dispersion of an aqueous emulsion of a finely divided (0.1-5 microns) wax material in a continuous phase made up of a small amount of an organopolysiloxane of prescribed viscosity in a large volume of a hydrocarbon solvent of prescribed aniline point and distillation range characteristics (see column 6, lines 19 et seq). The particulate wax/ water emulsion is dispersed in the organopolisiloxane/hydrocarbon solvent phase by means of a non-silicone type of water-in-oil emulsifier (see column 7, lines 14 et seq). Such wax polishing emulsions, however, have obvious disadvantages for cosmetic usage. For one thing, the hydrocarbon solvent is contraindicated for skin applications due to its inherent skin-drying characteristic, indeed skin-damaging upon prolonged contact. For another, the polishing waxes are inherently water resistant and form non-permeable films, which characteristics, although suitable for application to hard surfaces such as wood or metal, are undesirable in skin care compositions. The wax polishing emulsions of U.S. Pat. 4,013,475, therefore, teach away from the skin moisturizing o/w/s multiple emulsion compositions of the subject invention which form non-occlusive, air- and moisture-permeable films upon application to the skin.